1. Field of the Invention
The present invention relates to lamp sockets, and, more particularly, to fluorescent lamp sockets.
2. Description of the Related Art
Fluorescent lamps, as known, include a glass tube coated on the inside with phosphor powders which fluoresce when excited by ultraviolet light. The glass tube is filled with rare gases (such as argon, neon, and krypton) and a small amount of mercury, and operates at a relatively low pressure. Electrodes are mounted within the glass tube and emit electrons during operation. The electrons are accelerated by the voltage across the tube until they collide with mercury atoms, causing the mercury atoms to be ionized and excited. When the mercury atoms return to their normal state, photons corresponding to mercury spectral lines in both the visible and ultraviolet region are generated, thereby exciting the phosphor coating on the inside of the tube to luminance.
To start a fluorescent lamp, electron emission from the electrodes may be induced in one of two ways. First, a filament electrode may be heated by passing current therethrough. Secondly, a high voltage which is sufficient to start an electric discharge in the lamp may be applied across the lamp without preheating the electrodes. Instant start circuits which are commonly used today typically employ the latter method of inducing electron emission from the electrodes. Instant start circuits use a ballast which applies a high voltage (e.g., up to 848 VAC) at a high frequency. Such instant start ballasts are much more energy efficient than older style ballasts which heat the electrodes.
A problem associated with fluorescent lamps utilizing an instant start ballast is that the high voltage applied to the electrodes by the ballast can also cause electrical arcing to occur between a contact pin of the fluorescent lamp and the conductor of the fluorescent lamp holder in which the fluorescent lamp is installed. For example, known fluorescent lamp holders may include slots for receiving the two respective contact pins of the fluorescent lamp therein. However, with conventional designs, if the contact pins are not correctly inserted into the socket, it is possible for one of the contact pins to be fully disengaged with the conductor, with the other contact pin being disposed a small distance away from the conductor (e.g., 0.030 inch). Alternatively, it is possible for each of the contact pins to be disposed a small distance away from the conductor (e.g., 0.030 inch). In either event, the high voltage applied to the contact pins by the instant start ballast may result in electrical arcing between the conductor and the contact pin disposed the small distance therefrom. Such electrical arcing is clearly not desirable.
Similarly, with fluorescent lamps utilizing a rapid start ballast, a two-piece conductor is used to contact each respective contact pin. It is possible for one of the contact pins to be fully engaged with the conductor, while the other contact pin is disposed a small distance away from the conductor (e.g., 0.030 inch). Under such conditions, the high voltage applied to the conductor (e.g., 220 VAC) may result in electrical arcing between the conductor and contact pins.
What is needed in the art is a fluorescent lamp holder which prevents electrical arcing between a conductor of the lamp holder and the contact pins of a fluorescent lamp.